Little explorations with HP calculators (no Prime)

03162018, 08:29 PM
Post: #272




RE: Little explorations with HP calculators (no Prime)
(03162018 07:48 PM)pier4r Wrote: Question to the RPN masters. Can one pass functions to a RPN program? For example a label that then is used by the program to recall another program. In other words the main program doesn't know a priori which other program to call, this will be defined by the value of an argument. Sure. This has been done since the Seventies when the first programmable calculators with indirect addressing were available. You can pass a label number on the stack, or with calculators like the HP41/42 a program name in alpha, and this can then be called indirectly. Example for HP41: call an equation solver with two guesses (1 and 2) in X and Y and the function to solve ("MYFUNC") in alpha 1 ENTER 2 "MYFUNC" XEQ "SOLVE" ... LBL "SOLVE" STO 02 X<>Y STO 01 ASTO 00 RCL 01 XEQ IND 00 STO 03 RCL 02 XEQ IND 00 STO 04 ... LBL"MYFUNC" X^2 2 – RTN You can even do this with an HP67: simply pass the label number. The called program stores this in register I and then does a GSB i. This is also possible for LBL A ... LBL e which are encoded with index 10...19. Dieter 

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